Botswana: Mass death of elephants - Is it due to the toxins in the drinking fountain?

Recently CNN.co.jp reported the following:

ゾウの大量死、水飲み場の毒素が原因か　ボツワナ

2020.09.22 Tue posted at 09:57 JST

（ＣＮＮ） アフリカ南部のボツワナで野生のゾウ３００頭以上が死んでいるのが見つかった問題で、政府の野生生物保護当局は２１日、毒素を生成するシアノバクテリア（藍色細菌）が水飲み場で繁殖していたことが原因だったと発表した。しかし、一部の専門家はこの説明に納得していない。

ゾウの死骸は今年５月から７月までの３カ月の間に相次いで見つかった。当初は原因不明とされ、さまざまな憶測が飛び交う中で、ボツワナ政府は死骸や土壌、水質の検査を指示していた。

シアノバクテリアは水の中で繁殖する細菌だが、全てが毒素を生成するわけではない。しかし専門家は、地球温暖化に伴う水温の上昇で細菌が繁殖しやすい条件が整い、シアノバクテリアが生成する毒素が増えることを懸念している。

ボツワナに生息するアフリカゾウは１３万頭と、アフリカ大陸で最も多い。同国は昨年、ゾウの狩猟解禁に踏み切って国際社会の非難の的になった。

保護団体の関係者などは、５月に死んだゾウについて、密猟によって殺された疑いがあると指摘していた。

しかしボツワナ野生生物・国立公園局の当局者は２１日の記者会見で、人が関与した可能性はほぼ全面的に排除されたと述べ、「入手できる証拠を見る限り、これは自然現象だった」と説明した。

さらに、死んだゾウは全て牙が抜き取られていなかったことも、ゾウの大量死が自然現象だったという政府の見解の裏付けになると述べ、「密猟の可能性は排除された」とした。

それでも納得しない専門家は、政府の調査結果の全面的な開示を求めている。ゾウを専門とする生物学者のキース・リンゼイ氏は、「水飲み場が原因だったとすれば、なぜゾウだけが影響を受けたのか」と疑問を投げかけている。

Translation

(CNN) About the problem that more than 300 wild elephants were found dead in Botswana of southern Africa, on the 21^st officials of the government wildlife protection bureau said that the cause was that toxin-producing cyanobacteria were breeding in the drinking fountain. However, some experts were not convinced by this explanation.

Elephant carcasses were found one after another during the three months from May to July this year. Initially, the cause was unknown, and in the midst of various speculations, the Botswana government ordered inspections of carcasses, soil, and water quality.

Cyanobacteria were bacteria that grew in water, but not all produce toxins. However, experts were concerned that the rise in water temperature associated with global warming could create conditions for bacterial growth and increase the toxins produced by cyanobacteria.

The number of African elephants inhabiting Botswana was 130,000, which was the highest on the African continent. Last year, the country was criticized by the international community for lifting the ban on elephant hunting.

Conservation group officials had pointed out that the elephant that died in May was suspected of being killed by poaching.

However, officials from the Botswana Wildlife and National Park Service said at a press conference on the 21st that the possibility of human involvement was almost completely ruled out, and explained that "as far as the available evidence is concerned, this is a natural phenomenon."

Furthermore, seeing the fact that all dead elephants did not had their tusks removed, he said that he supported the government's view that mass elephant death was a natural phenomenon, "the possibility of poaching has been ruled out".

Those experts who still unconvinced were demanding a full disclosure of government findings. Keith Lindsay, a biologist who specialized in elephants, threw out the question that "If the drinking fountain was the cause, why were only elephants affected?"

              It is nice to note that the unnatural death of the elephants could draw the attention of the elephant experts. They are the protectors of the wild life and the natural environment.